Anionic surfactants carry a negative charge on the hydrophilic portion, usually in the form of a carboxylate, phosphate, sulfate or sulfonate. These surfactants find use in emulsion polymerization as well as in agricultural chemicals, personal care and household products, industrial and institutional cleaners. They function as emulsifiers, cleaners, wetting agents, foaming and frothing agents such as for shampoos, car washes, carpet shampoos, hand dishwashing, latex foaming, oil recovery and other industrial uses.
While surfactants generally have one hydrophilic group and one hydrophobic moiety, recently a group of compounds having two hydrophobic moieties and two hydrophilic groups have been introduced. These have become known as "Gemini surfactants" in the literature (Chemtech, March 1993, pp 30-33), and J. American Chemical Soc., 115, 10083-10090, (1993) and the references cited therein. Other surfactant compounds having two hydrophilic groups and two hydrophobic moieties have been disclosed but not referred to as Gemini surfactants.
It is known to sulfate, phosphate and carboxylate surfactants through functionalization of the hydroxyls.
However, secondary hydroxyl's undergo sulfation, phosphation or carboxylation poorly, leading to undesired by-products and/or high levels of acid or low product yields. The compounds of the invention contain primary hydroxyl groups which can be more efficiently functionalized.
There is also a need for new and more effective and efficient surfactants, as well as the need for mild surfactants which are biologically compatible in an ecologically sensitive environment. A new class of compounds has been developed which demonstrates improved surface-active properties that are further characterized as mild, and environmentally benign.